Downregulation of Runx2 by 1,25-Dihydroxyvitamin D3 Induces the Transdifferentiation of Osteoblasts to Adipocytes

1,25-Dihydroxyvitamin D₃ (1,25(OH)₂D₃) indirectly stimulates bone formation, but little is known about its direct effect on bone formation. In this study, we observed that 1,25(OH)₂D₃ enhances adipocyte differentiation, but inhibits osteoblast differentiation during osteogenesis. The positive role of 1,25(OH)₂D₃ in adipocyte differentiation was confirmed when murine osteoblasts were cultured in adipogenic medium. Additionally, 1,25(OH)₂D₃ enhanced the expression of adipocyte marker genes, but inhibited the expression of osteoblast marker genes in osteoblasts. The inhibition of osteoblast differentiation and promotion of adipocyte differentiation mediated by 1,25(OH)₂D₃ were compensated by Runx2 overexpression. Our results suggest that 1,25(OH)₂D₃ induces the transdifferentiation of osteoblasts to adipocytes via Runx2 downregulation in osteoblasts.     

Reciprocal Changes in miRNA Expression with Pigmentation and Decreased Proliferation Induced in Mouse B16F1 Melanoma Cells by l-Tyrosine and 5-Bromo-2′-Deoxyuridine

Background: Many microRNAs have been identified as critical mediators in the progression of melanoma through its regulation of genes involved in different cellular processes such as melanogenesis, cell cycle control, and senescence. However, microRNAs’ concurrent participation in syngeneic mouse B16F1 melanoma cells simultaneously induced decreased proliferation and differential pigmentation by exposure to 5-Brd-2′-dU (5’Bromo-2-deoxyuridine) and L-Tyr (L-Tyrosine) respectively, is poorly understood. Aim: To evaluate changes in the expression of microRNAs and identify which miRNAs in-network may contribute to the functional bases of phenotypes of differential pigmentation and reduction of proliferation in B16F1 melanoma cells exposed to 5-Brd-2′-dU and L-Tyr. Methods: Small RNAseq evaluation of the expression profiles of miRNAs in B16F1 melanoma cells exposed to 5-Brd-2′-dU (2.5 μg/mL) and L-Tyr (5 mM), as well as the expression by qRT-PCR of some molecular targets related to melanogenesis, cell cycle, and senescence. By bioinformatic analysis, we constructed network models of regulation and co-expression of microRNAs. Results: We confirmed that stimulation or repression of melanogenesis with L-Tyr or 5-Brd-2′-dU, respectively, generated changes in melanin concentration, reduction in proliferation, and changes in expression of microRNAs 470-3p, 470-5p, 30d-5p, 129-5p, 148b-3p, 27b-3p, and 211-5p, which presented patterns of coordinated and reciprocal co-expression, related to changes in melanogenesis through their putative targets Mitf, Tyr and Tyrp1, and control of cell cycle and senescence: Cyclin D1, Cdk2, Cdk4, p21, and p27. Conclusions: These findings provide insights into the molecular biology of melanoma of the way miRNAs are coordinated and reciprocal expression that may operate in a network as molecular bases for understanding changes in pigmentation and decreased proliferation induced in B16F1 melanoma cells exposed to L-Tyr and 5-Brd-2′-dU.     

1,25-二羟维生素D_3对成骨细胞增殖和分化的影响

成骨细胞是人和高等动物体内重要的功能细胞,在骨形成、骨发生以及骨内物质更新工程中发挥着重要的作用。1,25-二羟维生素D_3对成骨细胞的增殖和分化等过程具有重要影响。     

Galectin-3 Contributes to the Inhibitory Effect of lα,25-(OH)2D3 on Osteoclastogenesis

The active form of vitamin D, 1α,25-(OH)₂D₃, not only promotes intestinal calcium absorption, but also regulates the formation of osteoclasts (OCs) and their capacity for bone mineral dissolution. Gal-3 is a newly discovered bone metabolic regulator involved in the proliferation, differentiation, and apoptosis of various cells. However, the role of galectin-3 (gal-3) in OC formation and the regulatory effects of 1α,25-(OH)₂D₃ have yet to be explored. To confirm whether gal-3 contributes to the regulatory effects of 1α,25-(OH)₂D₃ on osteoclastogenesis, osteoclast precursors (OCPs) were induced by macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANKL). TRAP staining and bone resorption analyses were used to verify the formation and activation of OCs. qPCR, Western blotting, co-immunoprecipitation, and immunofluorescence assays were used to detect gene and protein expression. The regulatory effects of gal-3 in OC formation after treatment with 1α,25-(OH)₂D₃ were evaluated using gal-3 siRNA. The results showed that 1α,25-(OH)₂D₃ significantly increased gal-3 expression and inhibited OC formation and bone resorption. Expression levels of OC-related genes and proteins, matrix metalloproteinase 9 (MMP-9), nuclear factor of activated T cells 1 (NFATc1), and cathepsin K (Ctsk) were also inhibited by 1α,25-(OH)₂D₃. Gal-3 knockdown attenuated the inhibitory effects of 1α,25-(OH)₂D₃ on OC formation, activation, and gene and protein expression. In addition, gal-3 was co-localized with the vitamin D receptor (VDR). These data suggest that gal-3 contributes to the osteoclastogenesis inhibitory effect of lα,25-(OH)₂D₃, which is involved in bone and calcium homeostasis.     

Design and Synthesis of Fluoro Analogues of Vitamin D

The discovery of a large variety of functions of vitamin D₃ and its metabolites has led to the design and synthesis of a vast amount of vitamin D₃ analogues in order to increase the potency and reduce toxicity. The introduction of highly electronegative fluorine atom(s) into vitamin D₃ skeletons alters their physical and chemical properties. To date, many fluorinated vitamin D₃ analogues have been designed and synthesized. This review summarizes the molecular structures of fluoro-containing vitamin D₃ analogues and their synthetic methodologies.     

Micro-RNAs in Response to Active Forms of Vitamin D3 in Human Leukemia and Lymphoma Cells

Non-coding micro-RNA (miRNAs) regulate the protein expression responsible for cell growth and proliferation. miRNAs also play a role in a cancer cells’ response to drug treatment. Knowing that leukemia and lymphoma cells show different responses to active forms of vitamin D₃, we decided to investigate the role of selected miRNA molecules and regulated proteins, analyzing if there is a correlation between the selected miRNAs and regulated proteins in response to two active forms of vitamin D₃, calcitriol and tacalcitol. A total of nine human cell lines were analyzed: five leukemias: MV-4-1, Thp-1, HL-60, K562, and KG-1; and four lymphomas: Raji, Daudi, Jurkat, and U2932. We selected five miRNA molecules—miR-27b, miR-32, miR-125b, miR-181a, and miR-181b—and the proteins regulated by these molecules, namely, CYP24A1, Bak1, Bim, p21, p27, p53, and NF-kB. The results showed that the level of selected miRNAs correlates with the level of proteins, especially p27, Bak1, NFκB, and CYP24A1, and miR-27b and miR-125b could be responsible for the anticancer activity of active forms of vitamin D₃ in human leukemia and lymphoma.     

Does Vitamin D Work Synergistically with Anti-Asthmatic Drugs in Airway Remodeling?

Vitamin D is commonly known for its properties of airway remodeling inhibition. Due to this, we decided to analyze the action of calcitriol with anti-asthmatic drugs in airway remodeling. The HFL1 cell line was treated with calcitriol, beclomethasone 17-propionate, montelukast sodium, LTD4 and TGF-β in different combinations. Real-time PCR was used to analyzed the expression of ACTA2, CDH-1, Vimentin, ADAM33, MMP-9 and CysLTR1 on the mRNA level, whereas Western blot was used to analyze gene expression on the protein level. One-way analysis variants, the Kruskal-Wallis test, Student’s t-test or Welch’s t-test were used for statistical analysis. Concerning the results, pre-treatment with calcitriol increased the inhibitory effect of beclomethasone 17-propionate and montelukast sodium on the expression of ACTA2 (p = 0.0072), Vimentin (p = 0.0002) and CysLTR1 (p = 0.0204), and 1,25(OH)₂D₃ had an influence on the effects of beclomethasone 17-propionate and montelukast sodium and of CDH1 expression (p = 0.0076). On the protein level, pre-treatment with calcitriol with beclomethasone 17-propionate and montelukast sodium treatment decreased ACTA2 expression in comparison to the LT (LTD4 and TGF-β) control group (p = 0.0191). Hence, our study not only confirms that vitamin D may inhibit airway remodeling, but also shows that vitamin D has a synergistic effect with anti-asthmatic drugs.     

Investigation of the carbonation front shape on cementitious materials: Effects of the chemical kinetics

Carbonation depth-profiles have been determined by thermogravimetric analysis and by gammadensitometry after accelerated carbonation tests on ordinary Portland cement (OPC) pastes and concretes. These methods support the idea that carbonation does not exhibit a sharp reaction front. From analytical modelling, this feature is explained by the fact that the kinetics of the chemical reactions become the rate-controlling processes, rather than the diffusion of CO₂. Furthermore, conclusions are drawn as to the mechanism by which carbonation of Ca(OH)₂ and C-S-H takes place. Carbonation gives rise to almost complete disappearance of C-S-H gel, while Ca(OH)₂ remains in appreciable amount. This may be associated with the CaCO₃ precipitation, forming a dense coating around partially reacted Ca(OH)₂ crystals. The way in which CO₂ is fixed in carbonated samples is studied. The results indicate that CO₂ is chemically bound as CaCO₃, which precipitates in various forms, namely: stable, metastable, and amorphous. It seems that the thermal stability of the produced CaCO₃ is lower when the carbonation level is high. It is also shown that the poorly crystallized and thermally unstable forms of CaCO₃ are preferentially associated with C-S-H carbonation.     

An Overview of the Current Known and Unknown Roles of Vitamin D3 in the Female Reproductive System: Lessons from Farm Animals,Birds, and Fish

Recent studies have clearly shown that vitamin D₃ is a crucial regulator of the female reproductive process in humans and animals. Knowledge of the expression of vitamin D₃ receptors and related molecules in the female reproductive organs such as ovaries, uterus, oviduct, or placenta under physiological and pathological conditions highlights its contribution to the proper function of the reproductive system in females. Furthermore, vitamin D₃ deficiency leads to serious reproductive disturbances and pathologies including ovarian cysts. Although the influence of vitamin D₃ on the reproductive processes of humans and rodents has been extensively described, the association between vitamin D₃ and female reproductive function in farm animals, birds, and fish has rarely been summarized. In this review, we provide an overview of the role of vitamin D₃ in the reproductive system of those animals, with special attention paid to the expression of vitamin D₃ receptors and its metabolic molecules. This updated information could be essential for better understanding animal physiology and overcoming the incidence of infertility, which is crucial for optimizing reproductive outcomes in female livestock.     

1,25(OH)2D3 Inhibited Ferroptosis in Zebrafish Liver Cells (ZFL) by Regulating Keap1-Nrf2-GPx4 and NF-κB-hepcidin Axis

Ferroptosis is a kind of iron-dependent programed cell death. Vitamin D has been shown to be an antioxidant and a regulator of iron metabolism, but the relationship between vitamin D and ferroptosis is poorly studied in fish. This study used zebrafish liver cells (ZFL) to establish a ferroptosis model to explore the effect of 1,25(OH)₂D₃ on cell ferroptosis and its mechanism of action. The results showed that different incubation patterns of 1,25(OH)₂D₃ improved the survival rate of ZFL, mitigated mitochondrial damage, enhanced total glutathione peroxidase (GPx) activity, and reduced intracellular reactive oxygen species (ROS), lipid peroxidation (LPO), and malondialdehyde (MDA), as well as iron ion levels, with the best effect at 200 pM 1,25(OH)₂D₃ preincubation for 72 h. Preincubation of ZFL at 200 pM 1,25(OH)₂D₃ for 72 h downgraded keap1 and ptgs2 gene expression, increased nrf2, ho-1, fth1, gpx4a,b expression, and lowered the expression of the nf-κb p65,il-6,il-1β gene, thus reducing the expression of hamp1. The above results indicate that different incubation patterns of 1,25(OH)₂D₃ have protective effects on ferroptosis of ZFL induced by ferroptosis activator RSL3 and 1,25(OH)₂D₃ can inhibit ferroptosis of ZFL by regulating Keap1–Nrf2–GPx4 and NF-κB–hepcidin axis.     

Integrated nanophotonic hubs based on ZnO-Tb(OH)3/SiO2 nanocomposites

Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH)3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH)3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH)3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH)3/SiO2 as well as SnO2-Tb(OH)3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.     

Effect of High-Dose Vitamin D3 Intake on Ambulation, Muscular Pain and Bone Mineral Density in a Woman with Multiple Sclerosis: A 10-Year Longitudinal Case Report

Mounting evidence correlate vitamin D3 (cholecalciferol) supplementation or higher serum levels of vitamin D (25(OH)D) with a lower risk of developing multiple sclerosis (MS), reduced relapse rate, slower progression or fewer new brain lesions. We present here the case of a woman who was diagnosed with MS in 1990. From 1980 to 2000, her ability to walk decreased from ~20 to 1 km per day. Since January 2001, a vitamin D3 supplement was ingested daily. The starting dose was 20 mcg (800 IU)/day and escalated to 100 mcg (4000 IU)/day in September 2004 and then to 150 mcg (6000 IU)/day in December 2005. Vitamin D3 intake reduced muscular pain and improved ambulation from 1 (February 2000) to 14 km/day (February 2008). Vitamin D intake over 10 years caused no adverse effects: no hypercalcaemia, nephrolithiasis or hypercalciuria were observed. Bowel problems in MS may need to be addressed as they can cause malabsorption including calcium, which may increase serum PTH and 1,25(OH)2D levels, as well as bone loss. We suggest that periodic assessment of vitamin D3, calcium and magnesium intake, bowel problems and the measurement of serum 25(OH)D, PTH, Ca levels, UCa/Cr and bone health become part of the integral management of persons with MS.     

Stereoselective Synthesis of 24-Fluoro-25-Hydroxyvitamin D3 Analogues and Their Stability to hCYP24A1-Dependent Catabolism

Two 24-fluoro-25-hydroxyvitamin D₃ analogues (3,4) were synthesized in a convergent manner. The introduction of a stereocenter to the vitamin D₃ side-chain C24 position was achieved via Sharpless dihydroxylation, and a deoxyfluorination reaction was utilized for the fluorination step. Comparison between (24R)- and (24S)-24-fluoro-25-hydroxyvitamin D₃ revealed that the C24-R-configuration isomer 4 was more resistant to CYP24A1-dependent metabolism than its 24S-isomer 3. The new synthetic route of the CYP24A1 main metabolite (24R)-24,25-dihydroxyvitamin D₃ (6) and its 24S-isomer (5) was also studied using synthetic intermediates (30,31) in parallel.